The Associated Press

Circuit Judge John Markson ruled that the law does not violate union members’ rights to free speech and association.

The Wisconsin Law Enforcement Association had brought the challenge. In his 46-page ruling, Markson wrote that the law does not take anything away from workers to which they are constitutionally entitled, and that the state may put limits on the right to collective bargaining.

“The problem with the plaintiffs’ argument is that it conflates the right to collectively bargain, a statutory right, with freedom of association, a constitutional right,” Markson wrote. “They are not the same. The Legislature can limit (indeed it could abolish altogether) the statutory right to collectively bargain without infringing on the constitutional right of public employees to freely associate.”

Sally Stix, an attorney for the police union, told the Wisconsin State Journal (http://bit.ly/1ceHDjK ) she had not seen the decision, which was issued late Wednesday afternoon.

The case is the latest defeat for opponents of the law known as Act 10. Republican Gov. Scott Walker’s legislation effectively ended collective bargaining for most public workers.

The police union argued the law fractured the union into unequal parts — state troopers and inspectors, who retained their union rights as “public safety” employees, and “general” employees made up of Capitol and UW police officers and detectives, state Division of Motor Vehicle field agents and police communication officers.

Markson wrote that there “are equal protection implications to the creation of these classifications,” and that the public safety sector appears to be getting favorable treatment because many of its members endorsed Walker in the 2010 election. But the judge said it was a distinction that the Legislature was allowed to draw as long as there was a rational basis for it, such as avoiding a strike by vital public safety workers.

The judge also wrote that it might have been “rank political favoritism” to give preferential treatment to state troopers, “and if so, that is a shame, but if the law passes the rational basis test, it is also irrelevant.”

Even after Act 10, there is no reason that workers cannot gather together and advocate for whatever they want, even endorse political candidates for public office, Markson said.